I have a '99 R1 w/ 18000 miles. About 300 miles ago it started making a strange rattling sound. The power does not seem affected but the rattling is very noticeable. The sound gets louder and louder the warmer the motor gets. It almost sounds like the timing chain is slapping around inside the motor. I have replaced the timing chain tensioner to no avail. Any advice is greatly appreciated. Thanks.

Is the rattle always present ie; neutral/in gear, low rpm/high rpm, in sync with engine rpm, engine loaded or free spinning, on left or right (presume its on timing chain side), what does it sound like its in sync with, remember cams rotate half the speed of crank, have you changed the oil? Is it clean?.
Supply as much details as possible for a more accurate response of what the problem may be.

Yes the rattle is always present. The noise is louder at higher rpm's than it is at lower rpm's. The oil has been changed. The oil looked very clean when it was changed. The noise seems in sync with the rpms of the motor. The sound seems to be coming from the right side top of the motor. Would this be valve noise? I have not had the valves adjusted. The noise is the most apparent when letting off of the throttle.

check you head. possible bad lifter spring or valve issue. or we'll hope not but if it has a slight knock a piston might be going. at 18000 miles you are about do for a valve adjustment. on average its every 20000. but it depends on the rider/ owner.

Cam chain looseness sound disappear while engine reaches its OP temp.

It must be a loose valve.

Thanks for the replies. I was planning on taking it to the shop to have a valve job done but I was a little apprehensive to have any more work done to it if it was a major motor problem. I will let you know how it turns out.:hellobye

Originally posted by cotton133
Thanks for the replies. I was planning on taking it to the shop to have a valve job done but I was a little apprehensive to have any more work done to it if it was a major motor problem. I will let you know how it turns out.:hellobye

Just make sure you explain it to the guys at the shop and they will keep an eye out for anything astray when doing the valve adjustment.

I got my bike back from the shop today and I got some bad news. I was told that the noise was not a valve but the cam chain. The mechanic told me that he warmed the bike up and the strange rattling sound became noticeable once the bike reached proper operating temperature. He also said that the cam chain noise would start once the bike warmed up. MartinC has told me the exact opposite. From everything I have read and heard MartinC really seems to know his stuff. Is my mechanic incompetent? Should I take it somewhere else to have another mechanic to look at it? Thanks again.

I'm no expert on this but it may just be the tensioner. I know there is an aftermarket one that you can just bolt on. Pm Martin if he doesn't reply to this thread. I remember reading something about problems with tensioners somewhere but can't remember the details.

What I"d do if I were you:

Go back there,talk to the service manager (not the mechanic) and have him diagnose the problem himself;if he come the the same conclusion,let him do the work but have him write on the wrok order that the job is free if its not that...or the amount is applicable on a valve job.(but I take that they checked it).

Keep in mind that not all problems give the same symptoms.

Thanks for the replies. I have replaced the tensioner but it did not help. I will take the bike back and do as you said MartinC. Thanks again.:hellobye

does it clatter worse on the over-run than on the power, this would indicate to tensioner. Check it again, ensure it is extended and puting tension on the chain, remove timing inspection cover if necessary to verify.
sounds very like tensioner to me (but sounds arent always easy to interpret via text)

I think it is the tensioner as well but I have replaced it already. The tensioner was used from another bike that did not have the rattle. The only other experience I had with a worn out timing chain was in an old nissan I used to have. It sounded bad when it was cold but the noise got less noticeable when it reached the proper operating temperature. The noise does seem more noticeable at idle when you are revving it.